function Judge(a, b, c)
    if a > b then
        local t = a
        a = b
        b = t
    end
    if c < a then
        return Judge(c, a, b)
    elseif c < b  then
        return Judge(a, c, b)
    else
        if a + b <= c then
            return "non-triangle"
        else
            if a == b or b == c then
                if a == b and b == c then
                    return "equilateral triangle"
                else
                    return "isoceles triangle"
                end
            else 
                return "triangle"
            end
        end
    end
end

do
    local a = {}
    for i = 1, 3 do
        a[i] = io.read("*n")
        if type(a[i]) ~= "number" or a[i] <= 0 then
            print("error")
            os.exit()
        end
    end
    print(Judge(a[1], a[2], a[3]))
end